The LCD panel consumes a large percentage of the total power in cell phones, PDA etc. It is a constant challenge to reduce the power consumption of LCD panels while maintaining the same or better image quality. Burst operation is a commonly used method of adjusting LCD brightness in a backlight inverter. However, when burst operation is used, it's critical to choose a proper operation frequency in a given LCD panel in order to prevent panel flicker or display noise. Typically, different inverter modules are required since different LCD panels require different burst frequencies.
One solution to the above problem is to incorporate different oscillators with resistors and capacitors in different LCD panels. However, the manufacturing cost significantly increases.
Another solution is to use Display Power Saving Technology (DPST) and reduce backlight illumination by altering the image brightness and contrast within an image while maintaining overall display quality. With DPST technology, a graph card or panel generates a pulse-width-modulation (PWM) signal, whose duty cycle is used to adjust the lamp brightness and controlled by the relative brightness of the display. However, the frequency of PWM signals varies with different DPST technologies. As a result, different inverter modules are required to sense the duty cycle of PWM signals with different frequencies. It is desirable to have a universal inverter module suitable for different LCD panels and DPST technologies.